Can portable battery chargers receive and give charge simultaneously?

[kingmustard]

Can portable battery chargers receive power and offer power simultaneously?

 

Backstory:

 

I have an Android-based car head unit and a SIM card dedicated to providing the Internet to it.

 

I used to have the SIM card in a USB 4G dongle (connected to the head unit's USB port), which was able to create a 4G Wi-Fi hotspot, which the head unit was able to connect to.

 

The issue is that when the car is off, so is the dongle, meaning when the car comes back on, it takes the dongle 30 seconds or so to reconnect to the 4G network. This period, each time I get in my car, is annoying as I have to either wait, or start driving, before I can choose an Internet radio station. Starting to drive before choosing isn't ideal-safety-wise.

 

As an alternative, I am currently trying the SIM card in a basic Motorola Moto G (2015) instead, which is kept charged via. the USB port on the head unit. I have the phone's Wi-Fi hotspot enabled and this means that, as long as the phone has power, as soon as I turn my car on, the head unit has a ready-to-go Internet connection that it can auto-connect to, so I can connect to an Internet radio station before I even start moving.

 

However, if I am away from the car for three days or so, the phone will run out of battery and I'll have to turn it on and re-enable the Wi-Fi hotspot (when the phone is charged enough to power on, which usually takes 10 minutes or so).

 

My idea was to connect the portable battery charger to the head unit and to the phone, so that the portable battery charger charges itself from the head unit and keeps the phone charged at the same time.

[Chaftalie]

You are searching for an pass-thru PowerBank

 

like:

https://www.amazon.com/dp/B01K702S66/ref=sr_1_10?camp=217145&creative=399373&creativeASIN=B01K702S66&ie=UTF8&linkCode=as2&sr=1-10&tag=ianker-20

 

or (I think that one should fit you needs perfectly):

https://www.amazon.co.uk/Spigen-Essential-Backwards-Compatible-Technology/dp/B06XRLT1WD

[simson0606]

I have a Xiaomi power bank which can charge and supply power at the same time. I could check it with my own head unit and 4g stick (I have a similar setup)

The power bank may shut off after a while though...

[Origami Cactus]

You need a powerbank that will not turn itself off, when phone is fully charged.

[kingmustard]

1 minute ago, Origami Cactus said:

You need a powerbank that will not turn itself off, when phone is fully charged.

Any ideas?

 

I don't want to spend more than £20, ideally.

 

It only really needs to be around 4000-5000 mAh.

[Origami Cactus]

1 minute ago, kingmustard said:

Any ideas?

 

I don't want to spend more than £20, ideally.

 

It only really needs to be around 4000-5000 mAh.

No idea. I have an ancient (4 years old) Sony powerbank that is turned on all the time when usb is connected, and i also have an "intelligent" power bank, which you need to turn on with a button, but then it turns itself off, when the device is charged.

Best to read some reviews i think.